Chonnam Med J.  2003 Sep;39(3):143-148.

Conditions of Nitrate Reduction with Escherichio coli

• Park SH
• Joo SW
• Bae JA
• Lee KY

Abstract

NO, synthesized from L-arginine by NO synthase, is one of the biologically active molecules resulting in vasorelaxation, neurotransmission and cell killing. Although the assay of NO in biologic materials is getting more important, it is difficult to detect directly NO, because NO is a rapidlly oxidizable radical into nitrite and nitrate. Nitrate should be reduced to nitrite before reaction with Griess reagent. In this report, conditions of nitrate reduction by a kind of E. coli were determined. The nitrate reduction activity of the wild type E. coli, strain ATCC25922 was more potent 2-5 times than those of ATCC19215, JM105 and Y1090 strains. Reducing activity of E. coli homogenate was lower than that of intact E. coli. Heat treatment for 10 minutes above 60degrees C inactivated the nitrate reducing activity of E. coli. The optimal condition of nitrate reduction was that the reaction mixture contained nitrate 300 microM, 100 mM ammonium formate, pH 6.0, 0.25% intact E. coli (ATCC25922) was incubated at 37degrees C for 1 hour. These results suggest that the intact E. coli is useful for detection of nitric oxide metabolites.

Keyword

Nitric oxide; Nitrate reduction; E. coli

MeSH Terms

Ammonium Compounds
Arginine
Homicide
Hot Temperature
Hydrogen-Ion Concentration
Nitric Oxide
Nitric Oxide Synthase
Synaptic Transmission
Vasodilation
Arginine
Nitric Oxide
Nitric Oxide Synthase